title: Investigating a crow die-off in January-February 2011 during the introduction of a new clade of highly pathogenic avian influenza virus H5N1 into Bangladesh.
abstract: We investigated unusual crow mortality in Bangladesh during January-February 2011 at two sites. Crows of two species, Corvus splendens and C. macrorhynchos, were found sick and dead during the outbreaks. In selected crow roosts, morbidity was ~1 % and mortality was ~4 % during the investigation. Highly pathogenic avian influenza virus H5N1 clade 2.3.2.1 was isolated from dead crows. All isolates were closely related to A/duck/India/02CA10/2011 (H5N1) with 99.8 % and A/crow/Bangladesh/11rs1984-15/2011 (H5N1) virus with 99 % nucleotide sequence identity in their HA genes. The phylogenetic cluster of Bangladesh viruses suggested a common ancestor with viruses found in poultry from India, Myanmar and Nepal. Histopathological changes and immunohistochemistry staining in brain, pancreas, liver, heart, kidney, bursa of Fabricius, rectum, and cloaca were consistent with influenza virus infection. Through our limited investigation in domesticated birds near the crow roosts, we did not identify any samples that tested positive for influenza virus A/H5N1. However, environmental samples collected from live-bird markets near an outbreak site during the month of the outbreaks tested very weakly positive for influenza virus A/H5N1 in clade 2.3.2.1-specific rRT-PCR. Continuation of surveillance in wild and domestic birds may identify evolution of new avian influenza virus and associated public-health risks.
authors.affiliation: CCD, International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR, B), Dhaka, Bangladesh, sukhanbd@gmail.com.
authors.forename: Salah Uddin
authors.initials: SU
authors.lastname: Khan
authors.forename: Lashondra
authors.initials: L
authors.lastname: Berman
authors.forename: Najmul
authors.initials: N
authors.lastname: Haider
authors.forename: Nancy
authors.initials: N
authors.lastname: Gerloff
authors.forename: Md Z
authors.initials: MZ
authors.lastname: Rahman
authors.forename: Bo
authors.initials: B
authors.lastname: Shu
authors.forename: Mustafizur
authors.initials: M
authors.lastname: Rahman
authors.forename: Tapan Kumar
authors.initials: TK
authors.lastname: Dey
authors.forename: Todd C
authors.initials: TC
authors.lastname: Davis
authors.forename: Bidhan Chandra
authors.initials: BC
authors.lastname: Das
authors.forename: Amanda
authors.initials: A
authors.lastname: Balish
authors.forename: Ausraful
authors.initials: A
authors.lastname: Islam
authors.forename: Jens P
authors.initials: JP
authors.lastname: Teifke
authors.forename: Nord
authors.initials: N
authors.lastname: Zeidner
authors.forename: Steven
authors.initials: S
authors.lastname: Lindstrom
authors.forename: Alexander
authors.initials: A
authors.lastname: Klimov
authors.forename: Ruben O
authors.initials: RO
authors.lastname: Donis
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Luby
authors.forename: H L
authors.initials: HL
authors.lastname: Shivaprasad
authors.forename: Andrea B
authors.initials: AB
authors.lastname: Mikolon
mesh_terms: D000818:Animals; D001459:Bangladesh / Q000453:epidemiology; D016000:Cluster Analysis; D046368:Crows; D004196:Disease Outbreaks; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000821:virology*; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus